1. Field of the Art
The present invention relates to a method for detecting and correcting an error that has occcurred in a digital computer.
2. Prior Art
In a conventional digital computer, there are instances in which the contents of data are erroneously changed during data transmission or data processing, mainly due to hardware errors such as noise.
In a digital computer, numerical data are generally represented internally by binary numbers. For example, a numeral "9" in a decimal notation is internally represented by "1001" in a binary notation. Accordingly, a change in one bit of the most significant bit of the data due to noise or the like, causes the data to be internally represented as "0001". This presents a disadvantage that the representation "0001" is treated as "1" in the decimal notation. Further, it is not possible to correct the numerical data in which such error has taken place, to the original numeral "9" in the decimal notation.
As to character data, if a 2-bit error takes place in, for example, an ASCII code with a parity bit, such error cannot be detected and corrected.